diff --git a/galsim/moffat.py b/galsim/moffat.py
index 189d1b5605..d8b32bd936 100644
--- a/galsim/moffat.py
+++ b/galsim/moffat.py
@@ -43,7 +43,7 @@ class Moffat(GSObject):
 
     For more information, refer to
 
-        http://home.fnal.gov/~neilsen/notebook/astroPSF/astroPSF.html
+        https://ui.adsabs.harvard.edu/abs/1969A%26A.....3..455M/abstract
 
     A Moffat can be initialized using one (and only one) of three possible size parameters:
     ``scale_radius``, ``fwhm``, or ``half_light_radius``.  Exactly one of these three is required.
diff --git a/galsim/real.py b/galsim/real.py
index 8f12ad23a4..78cebd4e35 100644
--- a/galsim/real.py
+++ b/galsim/real.py
@@ -1265,7 +1265,7 @@ def _initialize(self, imgs, bands, xis, PSFs,
         # Note: put NSED axis last, since significantly faster to compute them this way,
         # even though we eventually convert to images which are strided in this format.
         coef = np.zeros((nk, nk, NSED), dtype=np.complex128)
-        Sigma = np.empty((nk, nk, NSED, NSED), dtype=np.complex128)
+        Sigma = np.zeros((nk, nk, NSED, NSED), dtype=np.complex128)
 
         # Solve the weighted linear least squares problem for each Fourier mode.  This is
         # effectively a constrained chromatic deconvolution.  Take advantage of symmetries.